1. Field of the Invention
This invention relates to waste material hammer mills for disposing of waste material with a minimum of plugging of the inlet to the mill while developing a downdraft flow of air away from the mill inlet.
2. Description of the Prior Art
The prior art relating to waste material hammer mills has failed to consider the way the waste material fed to the mill is handled by rotary hammers in cooperation with breaker plates and a grate assembly which encompasses substantially one-half of the hammer circle. The prior art is represented by Williams U.S. Pat. No. 3,667,694 3,806,048, 4,245,790 and 4,399,085 and Strom et al U.S. Pat. No. 4,009,836. Secondary prior art references include Lemmon et al U.S. Pat. No. 2,482,279 and West U.S. Pat. No. 2,767,929.
It has been determined from actual tests that when the breaker plates and cage bars are arranged in a specific manner to be disclosed hereinafter, the waste material can be processed in large quantities without encountering plugging at the inlet, and without developing objectionable blow-back in line of flow toward the inlet which has heretofore developed due to the fan effect of the rotary hammers. Another prior art reference is the brochure of the Pennsylvania Crusher Division Bath Iron Works Corporation of West Chester, Pennsylvania which is advertised to be a mill that inhibits the escape of dust through the feed inlet to the mill.